/*
 * Copyright (c) 2007-2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
package com.sun.org.apache.bcel.internal.classfile;

/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2001 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" and
 *    "Apache BCEL" must not be used to endorse or promote products
 *    derived from this software without prior written permission. For
 *    written permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    "Apache BCEL", nor may "Apache" appear in their name, without
 *    prior written permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */
import java.util.Stack;

/**
 * Traverses a JavaClass with another Visitor object 'piggy-backed'
 * that is applied to all components of a JavaClass object. I.e. this
 * class supplies the traversal strategy, other classes can make use
 * of it.
 *
 * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
 */
public class DescendingVisitor implements Visitor {
    private JavaClass clazz;
    private Visitor visitor;
    private Stack stack = new Stack();

    /** @return container of current entitity, i.e., predecessor during traversal
     */
    public Object predecessor() {
        return predecessor(0);
    }

    /**
     * @param level nesting level, i.e., 0 returns the direct predecessor
     * @return container of current entitity, i.e., predecessor during traversal
     */
    public Object predecessor(int level) {
        int size = stack.size();

        if ((size < 2) || (level < 0))
            return null;
        else
            return stack.elementAt(size - (level + 2)); // size - 1 == current
    }

    /** @return current object
     */
    public Object current() {
        return stack.peek();
    }

    /**
     * @param clazz Class to traverse
     * @param visitor visitor object to apply to all components
     */
    public DescendingVisitor(JavaClass clazz, Visitor visitor) {
        this.clazz = clazz;
        this.visitor = visitor;
    }

    /**
     * Start traversal.
     */
    public void visit() {
        clazz.accept(this);
    }

    public void visitJavaClass(JavaClass clazz) {
        stack.push(clazz);
        clazz.accept(visitor);

        Field[] fields = clazz.getFields();
        for (int i = 0; i < fields.length; i++)
            fields[i].accept(this);

        Method[] methods = clazz.getMethods();
        for (int i = 0; i < methods.length; i++)
            methods[i].accept(this);

        Attribute[] attributes = clazz.getAttributes();
        for (int i = 0; i < attributes.length; i++)
            attributes[i].accept(this);

        clazz.getConstantPool().accept(this);
        stack.pop();
    }

    public void visitField(Field field) {
        stack.push(field);
        field.accept(visitor);

        Attribute[] attributes = field.getAttributes();
        for (int i = 0; i < attributes.length; i++)
            attributes[i].accept(this);
        stack.pop();
    }

    public void visitConstantValue(ConstantValue cv) {
        stack.push(cv);
        cv.accept(visitor);
        stack.pop();
    }

    public void visitMethod(Method method) {
        stack.push(method);
        method.accept(visitor);

        Attribute[] attributes = method.getAttributes();
        for (int i = 0; i < attributes.length; i++)
            attributes[i].accept(this);

        stack.pop();
    }

    public void visitExceptionTable(ExceptionTable table) {
        stack.push(table);
        table.accept(visitor);
        stack.pop();
    }

    public void visitCode(Code code) {
        stack.push(code);
        code.accept(visitor);

        CodeException[] table = code.getExceptionTable();
        for (int i = 0; i < table.length; i++)
            table[i].accept(this);

        Attribute[] attributes = code.getAttributes();
        for (int i = 0; i < attributes.length; i++)
            attributes[i].accept(this);
        stack.pop();
    }

    public void visitCodeException(CodeException ce) {
        stack.push(ce);
        ce.accept(visitor);
        stack.pop();
    }

    public void visitLineNumberTable(LineNumberTable table) {
        stack.push(table);
        table.accept(visitor);

        LineNumber[] numbers = table.getLineNumberTable();
        for (int i = 0; i < numbers.length; i++)
            numbers[i].accept(this);
        stack.pop();
    }

    public void visitLineNumber(LineNumber number) {
        stack.push(number);
        number.accept(visitor);
        stack.pop();
    }

    public void visitLocalVariableTable(LocalVariableTable table) {
        stack.push(table);
        table.accept(visitor);

        LocalVariable[] vars = table.getLocalVariableTable();
        for (int i = 0; i < vars.length; i++)
            vars[i].accept(this);
        stack.pop();
    }

    public void visitLocalVariableTypeTable(LocalVariableTypeTable obj) {
        stack.push(obj);
        obj.accept(visitor);
        stack.pop();
    }

    public void visitStackMap(StackMap table) {
        stack.push(table);
        table.accept(visitor);

        StackMapEntry[] vars = table.getStackMap();

        for (int i = 0; i < vars.length; i++)
            vars[i].accept(this);
        stack.pop();
    }

    public void visitStackMapEntry(StackMapEntry var) {
        stack.push(var);
        var.accept(visitor);
        stack.pop();
    }

    public void visitLocalVariable(LocalVariable var) {
        stack.push(var);
        var.accept(visitor);
        stack.pop();
    }

    public void visitConstantPool(ConstantPool cp) {
        stack.push(cp);
        cp.accept(visitor);

        Constant[] constants = cp.getConstantPool();
        for (int i = 1; i < constants.length; i++) {
            if (constants[i] != null)
                constants[i].accept(this);
        }

        stack.pop();
    }

    public void visitConstantClass(ConstantClass constant) {
        stack.push(constant);
        constant.accept(visitor);
        stack.pop();
    }

    public void visitConstantDouble(ConstantDouble constant) {
        stack.push(constant);
        constant.accept(visitor);
        stack.pop();
    }

    public void visitConstantFieldref(ConstantFieldref constant) {
        stack.push(constant);
        constant.accept(visitor);
        stack.pop();
    }

    public void visitConstantFloat(ConstantFloat constant) {
        stack.push(constant);
        constant.accept(visitor);
        stack.pop();
    }

    public void visitConstantInteger(ConstantInteger constant) {
        stack.push(constant);
        constant.accept(visitor);
        stack.pop();
    }

    public void visitConstantInterfaceMethodref(ConstantInterfaceMethodref constant) {
        stack.push(constant);
        constant.accept(visitor);
        stack.pop();
    }

    public void visitConstantLong(ConstantLong constant) {
        stack.push(constant);
        constant.accept(visitor);
        stack.pop();
    }

    public void visitConstantMethodref(ConstantMethodref constant) {
        stack.push(constant);
        constant.accept(visitor);
        stack.pop();
    }

    public void visitConstantNameAndType(ConstantNameAndType constant) {
        stack.push(constant);
        constant.accept(visitor);
        stack.pop();
    }

    public void visitConstantString(ConstantString constant) {
        stack.push(constant);
        constant.accept(visitor);
        stack.pop();
    }

    public void visitConstantUtf8(ConstantUtf8 constant) {
        stack.push(constant);
        constant.accept(visitor);
        stack.pop();
    }

    public void visitInnerClasses(InnerClasses ic) {
        stack.push(ic);
        ic.accept(visitor);

        InnerClass[] ics = ic.getInnerClasses();
        for (int i = 0; i < ics.length; i++)
            ics[i].accept(this);
        stack.pop();
    }

    public void visitInnerClass(InnerClass inner) {
        stack.push(inner);
        inner.accept(visitor);
        stack.pop();
    }

    public void visitDeprecated(Deprecated attribute) {
        stack.push(attribute);
        attribute.accept(visitor);
        stack.pop();
    }

    public void visitSignature(Signature attribute) {
        stack.push(attribute);
        attribute.accept(visitor);
        stack.pop();
    }

    public void visitSourceFile(SourceFile attribute) {
        stack.push(attribute);
        attribute.accept(visitor);
        stack.pop();
    }

    public void visitSynthetic(Synthetic attribute) {
        stack.push(attribute);
        attribute.accept(visitor);
        stack.pop();
    }

    public void visitUnknown(Unknown attribute) {
        stack.push(attribute);
        attribute.accept(visitor);
        stack.pop();
    }
}
